Rarely the significant leukopenia may be associated with prolonged therapy. Very rarely, interstitial nephritis may occur. Hepatitis and cholestatic jaundice have been reported with some penicillins and beta-lactamase inhibitors. In common with other beta-lactam antibiotics, hemolytic anemia has been reported rarely with piperacillin and piperacillin/tazobactam. Many of the patients treated in clinical trials were severely ill and had multiple underlying disease and physiological impairments, making it difficult to determine causal relationship of adverse experiences to therapy with piperacillin and tazobactam.